6.2 Whenever possible, test the activity
of the culture to be used against a standard
control specimen (a positive control)
with known antibacterial activity.
6.3 To determine whether the antibacterial
activity is due to the antibacterial
agent, test a specimen of the same material
treated in exactly the same way withwhatever other finishing agents were
used, but without the antibacterial agent.
Many standard textile finishing chemicals,
especially crease resistant and permanent
press reagents, will often give
strong antibacterial activity even after
many washes.